.NET SerialPort DataReceived event not firing

port.DtrEnable = true;

This solved it for me, the DataTransmitReady flag was not enabled, so no data was received.

I can't say for sure, but there could be a threading issue. WPF handles threading differently, and the polling of the virtual port is asynchronous, I believe. Have you tried this with a Windows Forms or console application to prove that it can work at all?

I use the exact same setup, it works perfectly now but had to solve many many problems to get there.

Here is why my initial declaration looks like:

comControl = new SerialPort();

//This is important - determine your min nb of bytes at which you will fire your event, mine is 9
comControl.ReceivedBytesThreshold = 9; 

//register the event handlers
comControl.DataReceived += new SerialDataReceivedEventHandler(OnReceive);
comControl.PinChanged += new SerialPinChangedEventHandler(OnPinChanged);

I seperated the open port and close port methods since i often check if the com port has been closed.

public bool OpenPort()
{
    try
    {
        //must keep it open to maintain connection (CTS)
        if (!comControl.IsOpen)
        {
             comControl.Open();
             comControl.RtsEnable = true;
        }
    }
    catch (Exception e)
    {
        //error handling here
    }
}

Lastly, verify that your Virtual Com Port driver is installed properly and that you are using the right port, a plug and play for my adapter was not enough. If you want to create a sort of control that will allow you to pick the ports available at runtime, the following command will give you the available ports:

System.IO.Ports.SerialPort.GetPortNames()